iStock/Thinkstock(ROME, Italy) -- While the G-7 leaders meet in Canada, the world’s top oil company executives are gathering at the Vatican for a two-day conference on climate change and the possibility of countries' transitioning away from dependence on fossil fuels.

Senior executives from oil giants such as British Petroleum, Royal Dutch Shell, Norway's Equinor, Mexico's Pemex and ExxonMobil are expected today for the meeting in the exclusive venue of a frescoed 16th-century villa in the Vatican gardens, where many top-level Vatican conferences are held.

Major international financiers, asset managers and executives in charge of public pension funds are also expected to attend.

Pope Francis, who is expected to address the meeting on Saturday, strongly supported the Paris Climate Accord, and has implicitly criticized the United States for withdrawing from the agreement.

The conference, titled "Energy, Transition and Care for our Common Home," recalls the pontiff's major document on climate change in 2015, which he addressed to "every person living on the planet for an inclusive dialogue about how we are shaping the future of our planet."

Tight-lipped Vatican officials would not confirm who is attending the conference or whether the pope’s speech to the group would be made public after the event. The meeting, which has been promoted by Notre Dame University in Indiana, is not open to the press.

In the pope's heartfelt 2015 paper, "Laudato si," he focused on the environment and sustainable development, decrying environmental degradation and global warming while criticizing consumerism and irresponsible development.

"Climate change is a global problem with grave implications: environmental, social, economic, political and for the distribution of goods. It represents one of the principal challenges facing humanity in our day,” he wrote, warning of unprecedented destruction of ecosystems if mitigation efforts are not undertaken.

Pope Francis also warned of unprecedented destruction of ecosystems if prompt climate-change mitigation efforts are not undertaken.

At the conference that starts today, among those expected to speak are Cardinal Peter Turkson, head of the Vatican’s department for Promoting Human Development, who has worked hard with the pope on issues such as climate change.

Also today, with interesting timing, the Vatican released the preparatory document for a bishops' meeting on the Amazon region to be held in the Vatican in October. The document entitled, "Amazonia: New Paths for the Church and for an integral Ecology," covers a number of issues including the impact of extractive industries on the Amazon rainforest, "one of our planet’s largest reserves of biodiversity and fresh water."